Field of the Invention
The invention relates to a positioning device for a printing press having at least one guard adjustable within an adjustment range relative to an instantaneous pole axis in a first adjusting direction counter to gravity and in an opposed second adjusting direction, and having an energy storage for setting a variable support moment in opposition to a moment of weight resulting from the gravity and engaging with the guard. The invention also relates to a printing press having at least one guard which is adjustable within an adjustment range relative to an instantaneous pole axis in a first adjusting direction counter to gravity and in an opposed second adjusting direction.
Printing presses equipped with this type of adjustable guard have been made and sold, for example, by the firm Heidelberger Druckmaschinen A.G. under their model number CD102. They include, in particular, a guard covering the dryer segment, which is in the form of a kick plate. This plate can be pivoted between a horizontal position, wherein it covers a dryer section, and an upright position, the pivoting thereof being effected with respect to a stationary instantaneous pole axis. The guard has a spring assigned thereto, which sets a support moment in opposition to a moment resulting from the weight of the guard itself and engaging with the guard. This spring is loaded partly in tension and partly in torsion. The basic shape thereof is that of a U, with the legs of the U being many times shorter than the base of the U. The legs are joined in the form of a fixed fastening to the press frame, on both sides of the printing press, in such a position below the guard that the legs of the U are disposed in a substantially horizontal plane. In a middle region of the base of the U, the spring forms an elongated clip, which is disposed at an angle relative to the horizontal so that, in a substantially upright position of the guard established by a releasable lock, the clip is oriented upwardly without contacting the guard itself. During the pivoting of the guard from the upright position to the horizontal position, the clip comes into contact with the underside of the guard, and sets a support moment, which increases with increasing approach of the guard to the horizontal position thereof, into opposition with the moment resulting from the intrinsic weight of the guard itself.
In this manner, the required manual force for raising and lowering the guard is reduced.